1. Field of the Invention
Exemplary embodiments of the present invention relate to a communication system; and, more particularly, to a transmitter/receiver and a data transmission/reception method in a communication system, which transmit and receive complex signals of broadcasting data by using a vestigial sideband (VSB)/single sideband (SSB) modulation scheme.
2. Description of Related Art
In a next-generation communication system, much research is being actively conducted to provide services having various qualities of service (QoS) at high transmission rates. A digital broadcasting system may be taken as an example of the next-generation communication system, and a variety of methods have been proposed to quickly transmit various forms of image and voice data through limited resources. In other words, a variety of methods have been proposed to improve transmission efficiency of broadcasting data including various forms of image and voice data in the digital broadcasting system. In particular, methods for transmitting and receiving broadcasting data by using the VSB/SSB modulation scheme have been proposed to improve transmission efficiency per unit frequency in a double sideband (DSB) modulation scheme.
Meanwhile, when a current digital broadcasting system transmits broadcasting data by using the above-described VSB/SSB modulation scheme, the digital broadcasting system removes an SSB frequency component corresponding to redundancy among DSB frequency components of a real signal from the broadcasting data, and then transmits the broadcasting data. Therefore, it is difficult for the current digital broadcasting system to transmit complex signals composing broadcasting data, for example, in-phase (I) signals and quadrature-phase (Q) signals by using the VSB/SSB modulation scheme.
In other words, when the digital broadcasting system transmits broadcasting data composed of complex signals by using the VSB/SSB modulation scheme to improve the transmission efficiency per unit frequency, the digital broadcasting system removes Q signals from the complex signals of the broadcasting data, and transmits broadcasting data composed of only I signals. Since the broadcasting data composed of only I signals are transmitted, broadcasting data different from the broadcasting data composed of complex signals are transmitted and received. That is, since the digital broadcasting system does not transmit and receive broadcasting data including I/Q signals, but transmits and receives broadcasting data including only I signals, there is a limit to providing high-quality digital broadcasting to users.
Therefore, there is a demand for a method which transmits and receives complex signals composing broadcasting data by using the VSS/SSB modulation scheme to improve the transmission efficiency per unit frequency in a communication system, for example, a digital broadcasting system.